Regional differences in glucose clearance: effects of insulin and resistance training on arm and leg glucose clearance in older hypertensive individuals

The purpose of this study was to compare insulin's ability to stimulate glucose uptake in the arm and leg in a group of older hypertensive individuals (n = 13, 66 +/- 2 yr old). We also examined the effect of a 4-mo whole body resistance-training (RT) program on arm and leg glucose clearance (GC) during a hyperinsulinemic-euglycemic clamp. During the hyperinsulinemic-euglycemic clamp, GC was assessed by simultaneous measurement of arm and leg blood flow (BF) and assessment of fractional glucose extraction (GE) in blood samples from the brachial artery, brachial vein, and popliteal vein. At baseline, a significant main effect (arm vs. leg) demonstrated greater GC and BF in the arm than in the leg (P = 0.006 for GC and P = 0.012 for BF). Insulin significantly increased GE, BF, and GC in the arm and leg (main effects: P = 0.0001 for GE, P = 0.0001 for BF, and P = 0.0001 for GC) at baseline. However, the effect of insulin was similar in the arm and leg. After RT, a significant main effect (baseline vs. RT) demonstrated greater GE and GC in the leg (P = 0.024 for GE and P = 0.053 for GE), but not in the arm (P = 0.31 for GE and P = 0.14 for GC). No significant main effect (baseline vs. RT) for BF in the arm or leg was observed after RT. In conclusion, the greater GC in the arm than in the leg at baseline is primarily due to enhanced arm BF. Furthermore, whole body RT appears to increase GC in the leg but not in the arm.